Irrigating Alfalfa

(Jamie) Thanks for staying with us. Let’s catch up with Kyle and Dr. Anderson as they visit about irrigating alfalfa.
(Kyle) Hi this is Kyle Bauer. I have the opportunity to visit with Bruce Anderson. He’s with the University of Nebraska. Heard his presentation this morning about irrigating alfalfa and talked a lot about what that profile of moisture, how important that is to the yields. Can you talk about that just a bit on what that profile does to the alfalfa? (Bruce) When we’re looking at irrigating our alfalfa, one of the things that we discover very quickly is that it’s almost impossible for us to design an irrigation system that’s going to be able to meet all the water demands that the alfalfa plant has during the summertime. And so one of the things that we try to do early on in the season is to build up an extra soil/water reservoir that the plants will be able to tap into when the water demands become so great during the Summer that we can’t keep up with irrigation. That’s where building up a good profile during that early first growth period can be so valuable to us. I like to recommend that growers tend to get at first cutting to have their soil profile at field capacity, all the way down to about six to eight feet, so that they have plenty of reserve moisture there to take care of some of the extra water needs they’re going to have during the summer. (Kyle) Per cutting across the Plains, do we know about how much moisture per cutting that we’ll take either out of the soil or out of rainfall or out of irrigation? (Bruce) Well it certainly varies during the season. During the cooler time of the year, especially in the Springtime or late in the Fall, we may only need four to five inches of moisture to produce a ton of alfalfa. As we get into the heat of the summer, it’s not at all unusual to be looking at six, seven, eight inches of water being needed during that time. And that’s one of the reasons why it’s so hard to keep up with water demands during that hot period. (Kyle) Well if we can have two plus inches of moisture stored per foot of soil, if we have a clay or a loam soil, then how many feet can we expect those roots to explore or use? (Bruce) Age of stand really influences that to some extent. But if we are doing a good job of irrigating and allowing the alfalfa plants sometimes to dry down a little bit, so that they’re trying to grow into moisture that may be deeper, we may find that we do have the roots getting down in an irrigated soil maybe as much as six to eight feet deep. In dryland fields we may have roots that get down 10-12 feet deep especially as we get into a four, five, six year old fields. (Kyle) Now you mentioned this morning a good analogy when you’re planting alfalfa to get a good stand and I thought it was very graphic and easy for all of us to understand. (Bruce) One of the things that we need to have if we’re going to get a good quick, thick stand started is to have real good seed to soil contact. And a lot of the soil may be dead air spaces typically when we are planting in loose soil. So we want to firm that soil very effectively,rolling can be one of the ways of doing it, using irrigation water can firm it. But I like to check that field by looking at it and being a field that is so firm that we could actually very easily bounce a basketball on that field in order to get the kind of seed to soil contact we want for establishing alfalfa. (Kyle) We’re visiting with Bruce Anderson. He is with the University of Nebraska at Lincoln. This is Kyle Bauer reporting. Back to you Jamie.
(Jamie) Thanks, Kyle! Folks, come back after the break and meet Dr. Don Miller with Alforex Seeds.

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